(XV) Parasites (1)Coccidia, Amoebae and Flagellates Flashcards
Giardiasis Laboratory Diagnosis
- Stools for trophozoites, cysts
- Duodenal samples for trophozoites via duodenal drainage/duodenal capsule technique (enterotest)
- […] for Giardia antigen
Treatment
- Metronidazole 250 mg tid x 5 days
Giardiasis Laboratory Diagnosis
- Stools for trophozoites, cysts
- Duodenal samples for trophozoites via duodenal drainage/duodenal capsule technique (enterotest)
- Enzyme immunoassay/direct flourescence assay/cartridge for Giardia antigen
Treatment
- Metronidazole 250 mg tid x 5 days
Hepatic Amoebiasis
Clinical Presentation
- […]
- Liver […]
Diagnosis
- Stool examination
- […] (preferred)
- […] (preferred)
- Abscess aspiration (reddish brown liquid, trophozoites at abscess wall)
Treatment
- […] 750 mg tid x 7-10 days
Hepatic Amoebiasis
Clinical Presentation
- Fever
- Liver enlargement, tenderness (upper right quadrant), abscess
Diagnosis
- Stool examination
- Serology (preferred)
- Imaging (preferred)
- Abscess aspiration (reddish brown liquid, trophozoites at abscess wall)
Treatment
- Metronidazole 750 mg tid x 7-10 days
Intestinal Amoebiasis
Clinical Syndromes
- Asymptomatic cyst passer
- Symptomatic nondysenteric infection
- Amoebic dysentery (acute)
- Fulminant colitis
- Perforation (peritonitis)
- Amoeboma (amoebic granuloma)
- Perianal ulceration
Diagnosis
- […] examination for trophozoites/cysts
- Sigmoidoscopy
Treatment
- […] 500-750 mg tid x 10 days
Intestinal Amoebiasis
Clinical Syndromes
- Asymptomatic cyst passer
- Symptomatic nondysenteric infection
- Amoebic dysentery (acute)
- Fulminant colitis
- Perforation (peritonitis)
- Amoeboma (amoebic granuloma)
- Perianal ulceration
Diagnosis
- Stool examination for trophozoites/cysts
- Sigmoidoscopy
Treatment
- Metronidazole 500-750 mg tid x 10 days
Laboratory Diagnosis of Toxoplasmosis
Serodiagnosis (Preferred)
- Indirect immunofluorescence
- Enzyme immunoassay
- Assay for antigen for […] infection
- Assay for IgM for […] infection (low predictive value)
- Assay for IgG for […] infection
Isolation of organism
- I guess not? LOL
PCR
- for […] infections
- Amplification of 529-bp Toxoplasma repeat element (unknown function) that exists in 200-300 copies/genome
- More sensitive to B1 gene (35 copies/ genome)
Laboratory Diagnosis of Toxoplasmosis
Serodiagnosis (Preferred)
- Indirect immunofluorescence
- Enzyme immunoassay
- Assay for antigen for current infection
- Assay for IgM for current/recent infection (low predictive value)
- Assay for IgG for past infection
Isolation of organism
- I guess not? LOL
PCR
- for current infections
- Amplification of 529-bp Toxoplasma repeat element (unknown function) that exists in 200-300 copies/genome
- More sensitive to B1 gene (35 copies/ genome)
INSERTS TREATMENT CUZ I OCD LOL
Pathogenesis of Amoebiasis
Non-invasive
- Amoebae on […] surface
- […]symptomatic cyst passer (~90% of cases)
- […] diarrhoea, cramps, abdominal discomfort
Invasive
- Necrosis of mucosa – […]
- […]
- Hematophagous trophozoites
- Ulcer enlargement – colitis, peritonitis, occasional
amoeboma
- Metastasis – extraintestinal amoebiasis
Invasive: Extraintestinal amoebiasis
- Dissemination primarily via […]
- Predominantly liver (Amoebic abscess)
- Other sites infrequent (Brain, cutaneous, pulmonary)
* […] stools common
Pathogenesis of Amoebiasis
Non-invasive
- Amoebae on mucosa surface
- Asymptomatic cyst passer (~90% of cases)
- Non-dysenteric diarrhoea, cramps, abdominal discomfort
Invasive
- Necrosis of mucosa – **ulcer
- Dysentery
- Hematophagous trophozoites
- Ulcer enlargement – colitis, peritonitis, occasional
amoeboma
- Metastasis – extraintestinal amoebiasis
Invasive: Extraintestinal amoebiasis
- Dissemination primarily via blood stream (E.g. portal vein)
- Predominantly liver (Amoebic abscess)
- Other sites infrequent (Brain, cutaneous, pulmonary)
* Amoeba-free stools common
Pathogenesis of Giardiasis
Giardiasis is often asymptomatic, with acute symptoms
- 1-2 week incubation
- […] diarrhea (Bulky, frothy, greasy, foul-smelling stools but […] blood or mucus)
- Upper gastro-intestinal uneasiness, bloating, flatulence, belching, cramps, nausea, vomiting, anorexia
- Usually clears spontaneously (undiagnosed) but can persist and become chronic (recurrent diarrheal episodes)
Pathogenesis of Giardiasis
Giardiasis is often asymptomatic, with acute symptoms
- 1-2 week incubation
- Sudden explosive, watery diarrhea (Bulky, frothy, greasy, foul-smelling stools but NO blood or mucus)
- Upper gastro-intestinal uneasiness, bloating, flatulence, belching, cramps, nausea, vomiting, anorexia
- Usually clears spontaneously (undiagnosed) but can persist and become chronic (recurrent diarrheal episodes)
Pathophysiology of Toxoplasmosis
- Asymptomatic
- Acute toxoplasmosis ([…], […], […]
- Reactivation upon […]
Congenital infection TRIAD (RHI)
- […]
- […]
- […]
- Neonatal illness (jaundice, anaemia)
- Encephalitis
- Hepatomegaly, Splenomegaly
- Abortion/Stillbirth
Special trait:
- Risk […] with gestation age BUT severity […] with gestation age
Toxoplasmic Encephalitis
- Complication in […] patients resulting from immunocompromised state
- Recrudescence of a latent infection
- Multifocal disease
- No spread to other organs
- Progresses to convulsions
- Detected by CT or MRI ([…] lesions on CT)
Pathophysiology of Toxoplasmosis
- Asymptomatic
- Acute toxoplasmosis (Lymphadenopathy, Fever (PUO), Eye lesions (choroiditis, retinitis, uveitis)
- Reactivation upon immunosuppresion (e.g Organ transplants)
Congenital infection TRIAD (RHI)
- RetinoChoroiditis
- Hydrocephalus
- Intracerebral calcification
- Neonatal illness (jaundice, anaemia)
- Encephalitis
- Hepatomegaly, Splenomegaly
- Abortion/Stillbirth
Special trait:
- Risk increases with gestation age BUT severity decreases with gestation age
Toxoplasmic Encephalitis
- Complication in AIDS patients resulting from immunocompromised state
- Recrudescence of a latent infection
- Multifocal disease
- No spread to other organs
- Progresses to convulsions
- Detected by CT or MRI (Ring enhancing lesions on CT)
Contrast w rubella where risk AND severity both decreases with gestation age!!!
Recall the life cycle of toxoplasma gondii, and hence deduce the routes of infection of toxoplasmosis
- […] (Ingestion of […] containing sporozoites)
- […] (Ingestion of […] containing bradyzoites)
- […] (Infection from […] containing tachyzoites)
Recall the life cycle of toxoplasma gondii, and hence deduce the routes of infection of toxoplasmosis
- Cat faeces (Ingestion of oocysts containing sporozoites)
- Infected meat (Ingestion of cysts containing bradyzoites)
- Congenital infection during acute infection/organ transplants/blood transfusion (Infection from pseudocysts containing tachyzoites)
Similar to Entamoeba Histolytica, the infective stage of Giardia intestinalis is when it is in the […] form.
- Hence, it is also easy to deduce that mode of transmission is by […]
- Disease name abit diff. Its called […]
Similar to Entamoeba Histolytica, the infective stage of Giardia intestinalis is when it is in the cyst form.
- Hence, it is also easy to deduce that mode of transmission is by ingestion of cysts in food or water
- Disease name abit diff. Its called Giardiasis
The infective stage of Entamoeba Histolytica is when it is in the […] form.
- Hence, it is easy to deduce that mode of transmission is by […], and that the disease caused is […]
- Not infective in the […] form!! (motile feeding stage)
The infective stage of Entamoeba Histolytica is when it is in the cyst form.
- Hence, it is easy to deduce that mode of transmission is by ingestion of cysts in food or water, and that the disease caused is amoebiasis
- Not infective in the Trophozoites form!! (motile feeding stage)
Toxoplasma gondii Life Cycle
- Oocysts (containing […]) in cat faeces
- Cysts (containing […]) in tissues
- Pseudocysts (containing […]) in macrophages
Toxoplasma gondii Life Cycle
- Oocysts (containing sporozoites) in cat faeces
- Cysts (containing bradyzoites) in tissues
- Pseudocysts (containing tachyzoites) in macrophages
Tachyzoites (tachos = fast) refer to the rapidly growing life stage of T. gondii that has also been called endozoites or trophozoites.
Bradyzoites (brady = slow), also called cystozoites, are the life stage found in the tissue cyst and are believed to replicate slowly.
